Abstract

Diffusivity of Cu in amorphous is increased by low temperature annealing above but the increase is suppressed by adding to . To clarify the reasons, we investigated the structural difference between and . The results show that the low temperature annealing does not cause polycrystallization of but purges weakly bonded oxygen atoms from the bulk and decreases the film density. Adding to is shown to increase the coordination number of Ta–O, which results in the improved thermal stability.

Received 08 March 2010Accepted 21 August 2010Published online 17 September 2010

Acknowledgments:

The present work was conducted as part of the Key-Technology Research Project “Atomic Switch Programmed Device” and was supported by Japan’s Ministry of Education, Culture, Sports, Science, and Technology. The x-ray absorption spectroscopy measurements were carried out with the approval of Japan Synchrotron Research Institute (JASRI) (Proposal Nos. 2008B5931 and 2009B1826).